changes date validation method to try each format until a match is found
changes date validation method to try each format until a match is found

shamangeorge/beets,sampsyo/beets,jackwilsdon/beets,sampsyo/beets,ibmibmibm/beets,beetbox/beets,shamangeorge/beets,Kraymer/beets,beetbox/beets,pkess/beets,sampsyo/beets,jackwilsdon/beets,SusannaMaria/beets,Kraymer/beets,jackwilsdon/beets,shamangeorge/beets,sampsyo/beets,SusannaMaria/beets,Kraymer/beets,ibmibmibm/beets,pkess/beets,ibmibmibm/beets,SusannaMaria/beets,beetbox/beets,ibmibmibm/beets,shamangeorge/beets,SusannaMaria/beets,pkess/beets,jackwilsdon/beets,beetbox/beets,Kraymer/beets,pkess/beets